import { computed } from 'vue';

// type
import { Props, Data } from './types/tabs';

export default (props: Props, data: Data) => {
  // 是否有箭头
  const hasArrows = computed((): boolean => {
    return props.showArrows && data.isOverflowing;
  });

  // 导航样式
  const containerStyles = computed(() => {
    const height = props.height;

    const regexp = new RegExp(/[a-zA-Z]/g);

    // 是否有单位
    const isUnit = regexp.test(`${height}`);

    return {
      height: !isUnit ? `${height}px` : height,
      transform: `translate3d(-${data.scrollOffset}px, 0,0)`,
    };
  });

  // 没有找到可以激活的tab
  const noFindActiveTab = computed(() => {
    return data.tabs.findIndex((tab, index: number) => {
      return tab.tabName === props.modelValue || index === props.modelValue;
    });
  });

  // 激活的Index
  const activeIndex = computed(() => {
    return data.tabs.findIndex((tab, index: number) => {
      if (!props.modelValue) {
        return index === 0;
      }

      // 没有找到可以激活的tab 默认激活第一项
      if (noFindActiveTab.value === -1) {
        return index === 0;
      }

      return tab.tabName === props.modelValue || index === props.modelValue;
    });
  });

  // 激活的tab
  const activeTab = computed(() => {
    if (!data.tabs.length) {
      return undefined;
    }

    return data.tabs[activeIndex.value];
  });

  return {
    hasArrows,
    activeTab,
    activeIndex,
    containerStyles,
  };
};